I was thinking about this, it must be either 2014 or 2000 I would say, 2014 because of the number of dance songs making official number 1 or 2000 for the sheer number of dance songs making the top 40 in general (even considering the fast chart), and a lot of them made top 10 too. Although I suppose you could say it was 2011 because a lot of music had dance influence in the chart that year, even many of those by pop/R&B artists that didn't credit dance producers on it.

Recently; 2012-14 for all the massive dance hits; the peak of deep and progressive house, Swedish House Mafia and Avicii, before EDM truly blended in with pop music and before tropical house and future bass was ever a thing. Of course there are good examples of those genres but now when you look at the top end of the charts you have Rudimental making so-called tropical house that really is more pop than anything. Likewise David Guetta with watered down future bass and Calvin Harris now making funk/RnB (which I love by the way but it ain't really EDM).

Recently; 2012-14 for all the massive dance hits; the peak of deep and progressive house, Swedish House Mafia and Avicii, before EDM truly blended in with pop music and before tropical house and future bass was ever a thing. Of course there are good examples of those genres but now when you look at the top end of the charts you have Rudimental making so-called tropical house that really is more pop than anything. Likewise David Guetta with watered down future bass and Calvin Harris now making funk/RnB (which I love by the way but it ain't really EDM).

A lot of the synthpop songs of the 80s sound more dancey than those watered down tropical house and future bass songs now!

1999 and 2000 I would still say were the biggest years for dance, if you look at the amount of dance songs making top 40 (and more importantly there are a considerable amount of those making top 10), even considering how fast the chart was.

I think late 2013 up to whenever Lean On peaked has to be the best period considering the dance that was out before was pretty much in line with the trends in pop. Late 2013 was what really introduced deep house/tropical house/deep garage into the forefront without much of a pop background and showed the public that songs of that ilk can coincide with stuff like Animals. It was more revolutionary and went against the grain of what was popular then.

Au Seve now that was a tune. Must the biggest dance hit that never was of that era.

Also Gabriel by Joe Goddard and Valentina.

Also Bear Hug by 2 Bears, Big Bad Wolf by Duck Sauce and Lets Have A Kiki by The Scissor Sisters all preceded the revival of deep/tech house in the charts that would happen in 2013.

The earliest hit in the house revival was Get Out My Head by Redlight, which I was such a fan of I remember just listening to the chart show to hear. Also B Traits ft Elisabeth Troy - Fever, which I also liked, not as much as Get Out My Head though!

In terms of preceding the chilled house dance trend in Europe in general that started to become big in 2013 when Klangkarussell ft Will Heard - Sonnetanz (Sun Don't Shine) became a hit, I would say Edward Maya and Vika Jigulina - Stereo Love back in 2010 definitely was ahead of its time.